Step 1: Understanding the Concept:
In coordination chemistry, ligands are often denoted by abbreviations. The abbreviation 'en' stands for the bidentate ligand ethylenediamine (or ethane-1,2-diamine according to IUPAC). Its chemical formula is \(\text{H}_2\text{NCH}_2\text{CH}_2\text{NH}_2\).
Step 2: Key Formula or Approach:
Read the IUPAC nomenclature of the given complexes and identify which one contains the full name corresponding to the abbreviation 'en'.
Step 3: Detailed Explanation:
Let's review the ligands present in each of the given IUPAC names:
- (A) Tetraamminecopper (II) ion: Contains 'ammine' ligands (\(\text{NH}_3\)).
- (B) Bis(ethylenediamine) dithiocyanatoplatinum (IV): Explicitly contains 'ethylenediamine' ligands. The prefix 'bis' indicates there are two of these bulky bidentate ligands.
- (C) Pentacarbonyliron (0): Contains 'carbonyl' ligands (\(\text{CO}\)).
- (D) Tetracyanonickelate (II): Contains 'cyano' ligands (\(\text{CN}^-\)).
Therefore, the complex containing the 'en' ligand is option (B).
Step 4: Final Answer:
Option (B) is the correct answer.